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Endoscopic Ultrasound

  • An ultrasound performed from inside the stomach to get a closer look at the digestive tract
  • For detecting cancer, pancreatic cysts, stones, and chronic pancreatitis
  • The procedure typically takes 30 to 60 minutes
  • Involves Radiology & Biomedical Imaging


Ultrasound, as you may already know, is a type of imaging that converts high-frequency sound waves into detailed pictures that doctors can interpret to gain information about what’s going on inside your body. 

If you have a digestive complaint, doctors can use a special type of ultrasound called “endoscopic ultrasound” to learn more about your condition. This technology is like being able to see through the intestinal walls in order to evaluate problems involving the esophagus, stomach, colon and pancreas.

The most common use for endoscopic ultrasound is to diagnose and stage gastrointestinal cancers and evaluate the pancreas, says Yale Medicine’s Harry Aslanian, MD, a endoscopist, or gastroenterologist who specializes in diagnosing and treating digestive diseases via endoscopic procedures. 

Yale Medicine’s team of interventional endoscopists collaborate with expert colleagues in radiology, surgery, pathology and oncology in a multidisciplinary fashion to get the best results for every patient.

What is an endoscopic ultrasound?

An endoscopic ultrasound (EUS) is an ultrasound performed from inside the stomach to obtain images and information about your digestive tract and the surrounding tissue and organs. When you have this test, your doctor will pass an endoscope—a thin, flexible, lighted tube with a camera and ultrasound probe at its tip—through your mouth and down your esophagus. The goal is to inspect your esophagus, stomach and the first part of your small intestine.

According to Dr. Aslanian, EUS is usually just one of several types of diagnostic tests patients with digestive problems will undergo. “EUS provides information that is complementary to other imaging studies, such as CT, MRI and PET scans,” he explains. “EUS is the most accurate method to biopsy cystic and solid abnormalities of the pancreas.”

What medical conditions is an endoscopic ultrasound used for?

Doctors use the EUS procedure to gather information that helps them evaluate a variety of medical conditions including:

  • Cancer: EUS can accurately determine how deeply a tumor penetrates the digestive wall. By examining the size, shape and ultrasound appearance of adjacent lymph nodes, doctors are able to determine whether cancer has spread. This information is used to “stage” cancer.
  • Pancreatic cysts: EUS is used to determine if pancreatic cysts are benign, precancerous or cancerous.
  • Stones: EUS can visualize small stones in the bile duct and gallbladder that may not be detected with other imaging studies.
  • Chronic pancreatitis: EUS can help identify subtle changes in the pancreas caused by chronic pancreatitis (an inflammation of the pancreas that worsens over time). EUS can help determine if ERCP-guided therapy of the pancreas may be helpful. An ERCP (endoscopic retrograde cholangiopancreatography) uses an endoscope and X-rays to help doctors see tumors, blockages and stones in the pancreas and bile ducts. 

What if the endoscopic ultrasound shows something that requires biopsy?

During your EUS, your doctor may detect an abnormality in the pancreas, bile duct, intestinal wall or adjacent lymph node that needs to be biopsied. This can be done at the same time, during the same procedure.

Biopsies are obtained using a type of technology called fine needle aspiration (FNA) or fine needle biopsy (FNB). A thin needle will be passed through the endoscope and the digestive wall under ultrasound guidance. Once it reaches the site, it will take samples of lesions such as tumors, cysts or lymph nodes. The cells will then be examined by Yale Medicine’s expert pathologists and cytologists to make a diagnosis.

EUS can also be used to perform a celiac plexus block, which is an injection of pain medication that is often used to help people suffering from abdominal pain caused by pancreatic cancer. The celiac plexus is a bundle of nerves surrounding the celiac artery located near the top of the stomach. 

What should patients expect before, during and after an endoscopic ultrasound?

Preparation for an endoscopic ultrasound begins the night before. You must not eat or drink anything after midnight the night before your procedure. You will need to arrive at Smilow Cancer Hospital an hour before your scheduled procedure. A nurse will put an IV in your arm for sedation medication and hydration.

The procedure typically takes 30 to 60 minutes, depending on what the doctor finds. You will wake up in the recovery room and remain there for up to two hours. A companion must drive you home and we suggest that you rest for the remainder of the day. In most cases, a regular diet can be resumed later in the day. Your throat might feel slightly sore and your belly may feel bloated from the air inflated through the endoscope. 

What are the risks of endoscopic ultrasound?

“EUS is a very safe procedure, with a complication rate of about 1 in 1,000,” says Dr. Aslanian. Potential complications include reactions to the anesthesia medications, making a hole in the digestive wall or bleeding. If FNA is performed on the pancreas, there is a small risk of pancreatitis (inflammation of the pancreas), which causes abdominal pain, nausea and vomiting. 

What stands out about Yale Medicine’s approach to endoscopic ultrasound?

At Yale Medicine, patient care is planned by a multidisciplinary team of surgeons, oncologists, radiologists and pathologists. Our interventional endoscopists work closely with referring physicians to promptly perform procedures, offer consultations and discuss management options.

As a group, we perform more than 2,000 complex endoscopies a year, making us among the largest of its kind in New England. Performing such a high volume of these procedures gives our doctors valuable experience that translates to expertise.

We specialize in the latest, most advanced methods of diagnosing and treating complicated diseases of the pancreas, bile duct and gastrointestinal tract. We are also actively involved in education and research, including ways to lower the incidence of pancreatitis after ERCP and understanding the natural history of pancreas cysts, and acute and chronic pancreatitis.